Semiconductor test apparatus and semiconductor test method

ABSTRACT

A semiconductor test apparatus includes a chuck top on which a semiconductor wafer is mounted, and contact probes that contact measurement points of semiconductor chips formed on the semiconductor wafer, the chuck top includes a conductor that contacts a lower surface of the semiconductor wafer, a mounting table arranged below the conductor, and a first vacuum tube and a second vacuum tube connected to the mounting table, the conductor has a plurality of suction holes that are arranged in a spiral form in top view, in the mounting table, a flow pass communicating with the plurality of suction holes and having a spiral form in top view, the first vacuum tube is connected to an inner circumference portion of the flow pass, and the second vacuum tube is connected to an outer circumference portion of the flow pass.

BACKGROUND OF THE INVENTION Field of the Invention

The present disclosure relates to a semiconductor test apparatus and asemiconductor test method.

Description of the Background Art

A probe device has been proposed for improving the measurement accuracyand power consumption efficiency of electrical characteristic inspectionfor a power device (corresponding to a semiconductor wafer) havingelectrodes on both sides of a semiconductor substrate by materializingthe reduction in contact resistance and uniformity of contact resistancebetween a rear side electrode of a semiconductor substrate and themounting surface conductor of the chuck top on which the semiconductorsubstrate is mounted (see, for example, Japanese Patent ApplicationLaid-Open No. 2015-26765).

However, in the technique described in Japanese Patent ApplicationLaid-Open No. 2015-26765, a semiconductor wafer is sucked through thevacuum passage; therefore, the pressure loss increases in proportion tothe length of the vacuum passage. Therefore, while the suction force atthe central portion of the chuck top having a short vacuum passage ismaximized, at portions closer toward the outer circumferential side ofthe check top, the suction force becomes lower, causing a variation insuction force within the plane of the semiconductor wafer. There hasbeen a problem that the measurement accuracy of the semiconductor testlowers as a result of the variation in contact resistance between thesemiconductor wafer and the chuck top.

SUMMARY

An object of the present disclosure is to provide a technique capable ofsuppressing lowering in measurement accuracy due to a variation incontact resistance between a semiconductor wafer and a chuck top in asemiconductor test.

The semiconductor test apparatus according to the present disclosureincludes a chuck top and contact probes. On the chuck top, asemiconductor wafer is mounted. The contact probes contact measurementpoints of semiconductor chips formed on the semiconductor wafer. Thechuck top includes a conductor, a mounting table, and a first vacuumtube and a second vacuum tube. The conductor contacts the lower surfaceof the semiconductor wafer. The mounting table is arranged below theconductor. The first vacuum tube and the second vacuum tube areconnected to the mounting table. The conductor has a plurality ofsuction holes arranged in a spiral form in top view. On the mountingtable, a flow pass communicating with the plurality of suction holes andhaving a spiral form in top view is formed. The first vacuum tube isconnected to an inner circumference portion of the flow pass, and thesecond vacuum tube is connected to an outer circumference portion of theflow pass.

Accordingly, the first vacuum tube sucks from the inner circumferenceportion of the flow pass; therefore, the suction force decreases as itgoes from the inner circumference portion toward the outer circumferenceside of the flow pass. Meanwhile, the second vacuum tube sucks from theouter circumference portion of the flow pass; therefore, the suctionforce decreases as it goes from the outer circumference portion towardthe inner circumference side of the flow pass.

Consequently, the variation in the suction force in the plane of thesemiconductor wafer becomes small, and the variation in the contactresistance between the semiconductor wafer and the chuck top alsobecomes small. As a result, in the semiconductor test, the suppressionof lowering in measurement accuracy due to a variation in the contactresistance between the semiconductor wafer and the chuck top is ensured.

These and other objects, features, aspects and advantages of the presentinvention will become more apparent from the following detaileddescription of the present invention when taken in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of a semiconductor test apparatus accordingto Embodiment 1;

FIG. 2 is a top view of a chuck top included in the semiconductor testapparatus according to Embodiment 1;

FIG. 3 is a top view of the chuck top included in the semiconductor testapparatus according to Embodiment 1 as viewed from above a mountingtable;

FIG. 4 is a cross-sectional view taken along the line A-A of FIG. 3:

FIG. 5 is a flowchart for a semiconductor test method according toEmbodiment 1;

FIG. 6 is a top view of a chuck top included in a semiconductor testapparatus according to Embodiment 2;

FIG. 7 is a top view of the chuck top included in the semiconductor testapparatus according to Embodiment 2 as viewed from above a mountingtable;

FIG. 8 is a cross-sectional view taken along the line B-B of FIG. 7;

FIG. 9 is a diagram of Embodiment 3, corresponding to FIG. 8;

FIG. 10 a top view of a chuck top included in a semiconductor testapparatus according to Embodiment 4;

FIG. 11 is a top view of the chuck top included in the semiconductortest apparatus according to Embodiment 4 as viewed from above a mountingtable;

FIG. 12 is a cross-sectional view taken along the line C-C of FIG. 11;

FIG. 13 is a diagram of Embodiment 5, corresponding to FIG. 12;

FIG. 14 a top view of a chuck top included in a semiconductor testapparatus according to Embodiment 6;

FIG. 15 is a top view of the chuck top included in the semiconductortest apparatus according to Embodiment 6 as viewed from above a mountingtable;

FIG. 16 is a cross-sectional view taken along the line D-D of FIG. 15;and

FIG. 17 is a diagram of Embodiment 7, corresponding to FIG. 16.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1

Hereinafter, Embodiment 1 will be described with reference to thedrawings. FIG. 1 is a schematic view of a semiconductor test apparatusaccording to Embodiment 1.

As illustrated in FIG. 1, the semiconductor test apparatus includes achuck stage 12, a chuck top 9, a tester 13, a test jig 14, contactprobes 15, and a transfer arm 16. The semiconductor test apparatusfurther includes a control unit (not illustrated) that controls eachpart of the semiconductor test apparatus, a transport hand (notillustrated) for mounting a semiconductor wafer 11 on the chuck top 9, asensor (not illustrated) for capturing features of the semiconductorwafer 11. Here, the control unit is, for example, a processor.

The chuck top 9 is mounted on the upper surface of the chuck stage 12.The semiconductor wafer 11 subject to the semiconductor test is placedon the upper surface of the chuck top 9.

The test jig 14 is held by the transfer arm 16 so as to be located abovethe semiconductor wafer 11. The contact probes 15 are fixed to the testjig 14 and moveable with the transfer operation of the transfer arm 16.The contact probes 15 are, for example, spring probes, wire probes,measuring needles, or the like, and may be the ones that aresurface-treated by such as gold plating.

The contact probes 15 and the tester 13 are electrically connected. Withthe contact probes 15 being in contact with the measurement points ofthe semiconductor chip (not illustrated) formed on the semiconductorwafer 11, the tester 13 measures the electrical characteristics of thesemiconductor chip via the contact probes 15, and determines whether ornot the semiconductor chip is a defective product based on themeasurement result.

Next, the configuration of the chuck top 9 will be described withreference to FIGS. 2 to 4. FIG. 2 is a top view of the chuck top 9. FIG.3 is a top view of the chuck top 9 as viewed from above a mounting table4. FIG. 4 is a cross-sectional view taken along the line A-A of FIG. 2.

As illustrated in FIGS. 2 to 4, the chuck top 9 includes a conductor 1,the mounting table 4, a vacuum tube 5, and a vacuum tube 6. Here, thevacuum tube 5 corresponds to a first vacuum tube, and the vacuum tube 6corresponds to a second vacuum tube. Although the vacuum tube 5 and thevacuum tube 6 are not illustrated in FIG. 2, the description thereofwill be made assuming that the vacuum tube 5 and the vacuum tube 6 arepresent.

The conductor 1 is formed in a disk shape and has an upper surface thatcontacts the lower surface of the semiconductor wafer 11. The mountingtable 4 is formed in a short columnar shape and is arranged below theconductor 1. The conductor 1 has a plurality of suction holes 2 formedtherein. The plurality of suction holes 2 are circular holes of the samesize, and are arranged in a spiral form in top view. In the mountingtable 4, a flow pass 7 communicating with the plurality of suction holes2 and having a spiral form in top view is formed. The flow pass 7 isformed so as to face the plurality of suction holes 2. Further, thecross-sectional areas of the flow pass 7 of the inner circumferentialside are the same as that of the outer circumferential side thereof.That is, the depth of the flow pass 7 of the inner circumferential sideis the same as that of the outer circumferential side thereof.

A plurality of positioning pins 10 are provided, in a state ofprotruding upward, on the upper surface of the mounting table 4 on theouter circumferential side out from the flow pass 7. Further, atpositions on the lower surface of the conductor 1 facing the pluralityof positioning pins 10, a plurality of holes 1 a into which theplurality of positioning pins 10 are inserted are formed. When theconductor 1 is placed on the mounting table 4 with the plurality ofpositioning pins 10 positioned in the plurality of holes 1 a, air suckedthrough the plurality of suction holes 2 flows through the flow pass 7due to the communication of the plurality of suction holes 2 and theflow pass 7. Note that in FIG. 3, the positioning pins 10 are notillustrated.

The conductor 1 and the mounting table 4 are made of a conductivematerial such as oxygen-free copper, pure copper, iron-based metal, oraluminum. Further, the conductor 1 and the mounting table 4 may besubjected to a surface treatment such as gold plating.

As illustrated in FIG. 3, one end portion of the vacuum tube 5 passesthrough the side surface of the mounting table 4 and is connected to theinner circumference portion of the flow pass 7 (specifically, an end ofthe inner circumference portion of the flow pass 7) formed in themounting table 4. One end portion of the vacuum tube 6 passes throughthe side surface of the mounting table 4 and is connected to the outercircumference portion of the flow pass 7 (specifically, an end of theouter circumference portion of the flow pass 7) formed in the mountingtable 4. Further, the other end portions of the vacuum tube 5 and thevacuum tube 6 are connected to, for example, a vacuum pump (notillustrated).

First, when air is sucked from the vacuum tube 5, it is sucked from theinner circumference portion toward the outer circumference portion ofthe flow pass 7. That is, the semiconductor wafer 11 is sucked from theinner circumference portion toward the outer circumference portion;therefore, the wrinkles generated on the semiconductor wafer 11 arestretched, and the semiconductor wafer 11 is adsorbed to the uppersurface of the conductor 1. Next, when air is sucked from the vacuumtube 6, it is sucked from the outer circumference portion toward theinner circumference portion of the flow pass 7, so that thesemiconductor wafer 11 is sucked more strongly on the upper surface ofthe conductor 1.

The suction force of the vacuum tube 5 is highest at the central portionof the conductor 1, which is the inner circumference portion of theconductor 1. Since the pressure loss increases in proportion to thelength of the flow pass 7, the suction force of the vacuum tube 5becomes lower toward the outer circumferential side of the conductor 1.On the other hand, the suction force of the vacuum tube 6 is maximizedat the outer circumference portion of the conductor 1. Then, thepressure loss increases in proportion to the length of the flow pass 7,the suction force becomes lower toward the center side of the conductor1. Consequently, the difference in suction force between the centralportion and the outer circumference portion of the conductor 1 isreduced, so that the variation in suction force within the plane of thesemiconductor wafer 11 is reduced. As a result, the contact resistancebetween the semiconductor wafer 11 and the conductor 1 becomes uniform,improving the measurement accuracy of the semiconductor test.

Next, the semiconductor test method will be described with reference toFIG. 5. FIG. 5 is a flowchart for a semiconductor test method.

As illustrated in FIG. 5, first, the control unit (not illustrated)causes the transport hand (not illustrated) to place the semiconductorwafer 11 on the upper surface of the chuck top 9 (Step S1). Then, whenthe control unit starts suction from the vacuum tube 5, thesemiconductor wafer 11 is sucked from the inner circumference portiontoward the outer circumference portion (Step S2). Next, when the controlunit starts suction from the vacuum tube 6, the semiconductor wafer 11is sucked from the outer circumference portion toward the innercircumference portion (Step S3). As a result, the semiconductor wafer 11is adsorbed to and held by the chuck top 9.

As described above, by starting suction from the vacuum tube 5 beforethe vacuum tube 6, the semiconductor wafer 11 is first sucked from theinner circumference portion to the outer circumference portion, so thatthe effect of stretching wrinkles generated on the semiconductor wafer11 is obtained.

Next, the control unit recognizes, as a feature of the semiconductorwafer 11, a feature such as electrode pads or the like of a plurality ofsemiconductor chips formed on the semiconductor wafer 11 by a sensor(not illustrated) such as a camera (Step S4). The control unitcalculates the amount of displacement between the electrode pads of thesemiconductor chips and the contact probes 15 and corrects the amount ofdisplacement (Step S5). The control unit moves the transfer arm 16 basedon the corrected amount of displacement to align the positions of thecontact probes 15 with respect to the electrode pads of thesemiconductor chips and brings the tips of the contact probes 15 intocontact with the measurement points of the semiconductor chips (StepS6).

The control unit confirms that the contact probes 15 and the measurementpoints of the semiconductor chips are electrically connected, andapplies a voltage or current to the semiconductor chips by the tester 13to measure the electrical characteristics of the semiconductor chips(Step S7), and record measured values (Step S8). Here, the measuredvalues may be recorded in a storage unit provided on the semiconductorchips, or may be recorded in a storage unit provided outside thesemiconductor test apparatus.

Next, the control unit moves the transfer arm 16 to retract the contactprobes 15 from the semiconductor chips (Step S9), and then determineswhether or not the measurement of all the semiconductor chips containedin the semiconductor wafer 11 is completed (Step S10). When themeasurement of all the semiconductor chips is not completed (Step S10:NO), the control unit moves the chuck stage 12 to move the semiconductorchips following subject to the measurement on the chuck top 9 to underthe contact probes 15 (Step S12), and then the step proceeds to Step S6.

On the other hand, when the measurement of all the semiconductor chipsis completed (Step S10: YES), the control unit stops the suction fromthe vacuum tube 5 and the vacuum tube 6, and then causes the transporthand to transfer the semiconductor wafer 1 l 1 from the chuck top 9(Step S11), and the process ends.

As described above, in Embodiment 1, the semiconductor test apparatusincludes the chuck top 9 on which the semiconductor wafer 11 is mounted,and the contact probes 15 that contact the measurement points of thesemiconductor chips formed on the semiconductor wafer 11, the chuck top9 includes the conductor 1 that contacts the lower surface of thesemiconductor wafer 11, the mounting table 4 arranged below theconductor 1, and the vacuum tube 5 and vacuum tube 6 connected to themounting table 4, the conductor 1 has a plurality of suction holes 2that are arranged in a spiral form in top view, in the mounting table 4,In the mounting table 4, the flow pass 7 communicating with theplurality of suction holes 2 and having a spiral form in top view, thevacuum tube 5 is connected to the inner circumference portion of theflow pass 7, and the vacuum tube 6 is connected to the outercircumference portion of the flow pass 7.

Also, the semiconductor test method includes a step (a) mounting thesemiconductor wafer 11 on the chuck top 9, a step (b) sucking thesemiconductor wafer 11 by the vacuum tube 5, and sucking thesemiconductor wafer 11 by the vacuum tube 6, and a step (c) bringing thecontact probes 15 into contact with the measurement portions of thesemiconductor chips to measure the electrical characteristics of thesemiconductor chips.

Accordingly, the vacuum tube 5 sucks from the inner circumferenceportion of the flow pass 7; therefore, the suction force decreases as itgoes from the inner circumference portion toward the outer circumferenceside of the flow pass 7. Meanwhile, the vacuum tube 6 sucks from theouter circumference portion of the flow pass 7; therefore, the suctionforce decreases as it goes from the outer circumference portion towardthe inner circumference side of the flow pass 7.

Consequently, the variation in the suction force in the plane of thesemiconductor wafer 11 becomes small, and the variation in the contactresistance between the semiconductor wafer 11 and the chuck top 9 alsobecomes small. As a result, in the semiconductor test, the suppressionof lowering in measurement accuracy due to a variation in the contactresistance between the semiconductor wafer 11 and the chuck top 9 isensured. From the above, the yield of the semiconductor chips isimproved.

Further, the step (b) is a step of sucking the semiconductor wafer 11 bythe vacuum tube 5, and then sucking the semiconductor wafer 11 by thevacuum tube 6; therefore, by starting suction from the vacuum tube 5before the vacuum tube 6, the semiconductor wafer 11 is first suckedfrom the inner circumference portion to the outer circumference portion,allowing stretching of wrinkles generated on the semiconductor wafer 11.

Embodiment 2

Next, a semiconductor test apparatus according to Embodiment 2 will bedescribed. FIG. 6 is a top view of a chuck top 9A included in asemiconductor test apparatus according to Embodiment 2. FIG. 7 is a topview of the chuck top 9A as viewed from above the mounting table 4. FIG.8 is a cross-sectional view taken along the line B-B of FIG. 7. InEmbodiment 2, the same components as those described in Embodiment 1 aredesignated by the same reference numerals, and the description thereofis omitted.

In Embodiment 1, the vacuum tube 6 connected to the outer circumferenceportion of the flow pass 7 is provided, however, as illustrated in FIGS.6 to 8, in Embodiment 2, the chuck top 9A is provided with the conductor1, the mounting table 4 and the vacuum tube 5, and the vacuum tube 6 isnot provided.

Further, in the mounting table 4, instead of the flow pass 7, a flowpass 17 communicating with the plurality of suction holes 2 and having aspiral form in top view is formed. The flow pass 17 is formed so as toface the plurality of suction holes 2. One end portion of the vacuumtube 5 passes through the side surface of the mounting table 4 and isconnected to the inner circumference portion of the flow pass 17(specifically, an end of the inner circumference portion of the flowpass 17) formed in the mounting table 4.

Although the plurality of suction holes 2 are arranged in a spiral formin top view as in the case of Embodiment 1, the number of the suctionholes 2 is smaller than that in the case of Embodiment 1.

Further, the cross-sectional shapes of the flow pass 17 are larger onthe outer circumferential side than on the inner circumferential side.Specifically, the depth of the flow pass 17 is deeper on the outercircumferential side than on the inner circumferential side.Consequently, the pressure loss that increases in proportion to thelength of the flow pass 17 become uniform.

In terms of a semiconductor test method, processes are performed thatare the same processes as those illustrated in FIG. 5 from which Step S3and the process related to the second vacuum tube in Step 11 areexcluded; therefore the description thereof is omitted.

As described above, in Embodiment 2, the semiconductor test apparatusincludes the chuck top 9A on which the semiconductor wafer 11 ismounted, and the contact probes 15 that contact the measurement pointsof the semiconductor chips formed on the semiconductor wafer 11, thechuck top 9A includes the conductor 1 that contacts the lower surface ofthe semiconductor wafer 11, the mounting table 4 arranged below theconductor 1, and the vacuum tube 5 connected to the mounting table 4,the conductor 1 has a plurality of suction holes 2 that are arranged ina spiral form in top view, in the mounting table 4, In the mountingtable 4, the flow pass 17 communicating with the plurality of suctionholes 2 and having a spiral form in top view, the vacuum tube 5 isconnected to the inner circumference portion of the flow pass 17, andthe cross-sectional shapes of the flow pass 17 are larger on the outercircumferential side than on the inner circumferential side.

Also, the semiconductor test method includes a step (d) mounting thesemiconductor wafer 11 on the chuck top 9A, a step (e) sucking thesemiconductor wafer 11 by the vacuum tube 5, and a step (f) bringing thecontact probes 15 into contact with the measurement portions of thesemiconductor chips to measure the electrical characteristics of thesemiconductor chips.

Accordingly, the pressure loss that increases in proportion to thelength of the flow pass 17 becomes uniform; therefore, the variation inthe suction force in the plane of the semiconductor wafer 11 becomessmall, and the variation in the contact resistance between thesemiconductor wafer 11 and the chuck top 9A also becomes small. As aresult, in the semiconductor test, the suppression of lowering inmeasurement accuracy due to a variation in the contact resistancebetween the semiconductor wafer 11 and the chuck top 9A is ensured.

Embodiment 3

Next, a semiconductor test apparatus according to Embodiment 3 will bedescribed. FIG. 9 is a diagram of Embodiment 3, corresponding to FIG. 8.In Embodiment 3, the same components as those described in Embodiments 1and 2 are designated by the same reference numerals, and the descriptionthereof is omitted.

In Embodiment 3, a chuck top 9B includes the conductor 1, the mountingtable 4, the vacuum tube 5, and the vacuum tube 6 as in the case ofEmbodiment 1. In Embodiment 1, the cross-sectional areas of the flowpass 7 are the same on the inner peripheral side and the outerperipheral side, however, as illustrated in FIG. 9, in the mountingtable 4, instead of the flow pass 7, a flow pass 17 communicating withthe plurality of suction holes 2 and having a spiral form in top view isformed in Embodiment 3. The cross-sectional shapes of the flow pass 17are larger on the outer circumferential side than on the innercircumferential side; therefore, the pressure loss that increases inproportion to the length of the flow pass 17 becomes uniform.

The connection relationship between the flow pass 17 and the vacuum tube5 and the vacuum tube 6 is the same as the connection relationshipbetween the flow pass 7 and the vacuum tube 5 and the vacuum tube 6 inEmbodiment 1; therefore, the description thereof is omitted.

Further, the description of the semiconductor test method is omittedbecause of the same processes as those of Embodiment 1.

As described above, in Embodiment 3, the vacuum tube 5 sucks thesemiconductor wafer 11 from the inner circumference portion of the flowpass 17, and the vacuum tube 6 sucks the semiconductor wafer 11 from theouter circumference portion of the flow pass 17; therefore, thevariation in the suction force in the plane of the semiconductor wafer11 becomes small. Further, the cross-sectional areas of the flow pass 17are larger on the outer circumferential side than on the innercircumferential side; therefore, the pressure loss that increases inproportion to the length of the flow pass 17 becomes uniform.

Consequently, the effect of reducing the variation in suction force inthe plane of the semiconductor wafer 11 is enhanced more than that inthe case of Embodiment 1; therefore, the further suppression of loweringin measurement accuracy due to a variation in the contact resistancebetween the semiconductor wafer 11 and the chuck top 9 is ensured, inthe semiconductor test.

Embodiment 4

Next, a semiconductor test apparatus according to Embodiment 4 will bedescribed. FIG. 10 is a top view of a chuck top 9C included in asemiconductor test apparatus according to Embodiment 4. FIG. 11 is a topview of the chuck top 9C as viewed from above the mounting table 4. FIG.12 is a cross-sectional view taken along the line C-C of FIG. 11. InEmbodiment 4, the same components as those described in Embodiments 1 to3 are designated by the same reference numerals, and the descriptionthereof is omitted.

As illustrated in FIGS. 10 to 12, in Embodiment 4, the chuck top 9Cincludes the conductor 1, the mounting table 4, and the vacuum tube 5 asin the case of Embodiment 2, however, the plurality of suction holes 2formed in the conductor 1 have sizes that are larger on the outercircumferential side than on the inner circumferential side. That is,the sizes of the plurality of suction holes 2 gradually increase fromthe inner circumferential portion toward the outer circumferentialportion of the conductor 1. Further, the cross-sectional shapes of theflow pass 7 are the same as that of the outer peripheral side thereof.

While the cross-sectional shapes of the flow pass 7 are the same, thesizes of the plurality of suction holes 2 are larger on the outercircumferential side than on the inner circumferential side; therefore,the pressure loss that increases in proportion to the length of the flowpass 7 becomes uniform.

Further, the description of the semiconductor test method is omittedbecause of the same processes as those of Embodiment 2.

As described above, in Embodiment 4, the sizes of the plurality ofsuction holes 2 are larger on the outer circumferential side than on theinner circumferential side; therefore, the pressure loss that increasesin proportion to the length of the flow pass 7 becomes uniform. As aresult, the variation in suction force within the plane of thesemiconductor wafer 11 becomes small, and the variation in contactresistance between the semiconductor wafer 11 and the chuck top 9C alsobecomes small. As a result, in the semiconductor test, the suppressionof lowering in measurement accuracy due to a variation in the contactresistance between the semiconductor wafer 11 and the chuck top 9C isensured.

Embodiment 5

Next, a semiconductor test apparatus according to Embodiment 5 will bedescribed. FIG. 13 is a diagram of Embodiment 5, corresponding to FIG.12. In Embodiment 5, the same components as those described inEmbodiments 1 to 4 are designated by the same reference numerals, andthe description thereof is omitted.

As illustrated in FIG. 13, in Embodiment 5, a chuck top 9D includes theconductor 1, the mounting table 4, and the vacuum tube 5 as in the caseof Embodiment 4, however, a flow pass 17, instead of the flow pass 7, isprovided in the mounting table 4. Further, in Embodiment 5, in additionto the sizes of the plurality of suction holes 2 being larger on theouter circumferential side than on the inner circumferential side, thecross-sectional areas of the flow pass 17 are larger on the outercircumferential side than on the inner circumferential side.

Further, the description of the semiconductor test method is omittedbecause of the same processes as those of Embodiment 2.

As described above, in Embodiment 5, in addition to the sizes of theplurality of suction holes 2 being larger on the outer circumferentialside than on the inner circumferential side, the cross-sectional areasof the flow pass 17 are larger on the outer circumferential side than onthe inner circumferential side; therefore, the effect of reducing thevariation in the suction force in the plane of the semiconductor wafer11 is enhanced further, compared with the case of Embodiment 4, and inthe semiconductor test, the further suppression of lowering inmeasurement accuracy due to a variation in the contact resistancebetween the semiconductor wafer 11 and the chuck top 9 is ensured.

The conductor 1 in which the plurality of suction holes 2 formed inEmbodiments 4 and 5 is applicable to the semiconductor test apparatusaccording to Embodiment 1. In such a case, the effect of reducing thevariation in suction force in the plane of the semiconductor wafer 11 isenhanced more than that in the case of Embodiment 4; therefore, thefurther suppression of lowering in measurement accuracy due to avariation in the contact resistance between the semiconductor wafer 11and the chuck top is ensured, in the semiconductor test.

Embodiment 6

Next, a semiconductor test apparatus according to Embodiment 6 will bedescribed. FIG. 14 is a top view of a chuck top 9E included in asemiconductor test apparatus according to Embodiment 6. FIG. 15 is a topview of the chuck top 9E as viewed from above a mounting table 24. FIG.16 is a cross-sectional view taken along the line D-D of FIG. 15. InEmbodiment 6, the same components as those described in Embodiments 1 to5 are designated by the same reference numerals, and the descriptionthereof is omitted.

As illustrated in FIGS. 14 to 16, in Embodiment 6, the chuck top 9Eincludes a conductor 21, the mounting table 24, and a vacuum tube 20.

The conductor 21 is formed in a disk shape and has an upper surface thatcontacts the lower surface of the semiconductor wafer 11. The mountingtable 24 is formed in a short columnar shape and is arranged below theconductor 21. The conductor 21 has the plurality of suction holes 2formed therein. The plurality of suction holes 2 are circular holes ofthe same size, and are arranged in a region thereof other than the outercircumferential portion. That is, the plurality of suction holes 2 arearranged in a substantially circular shape when viewed from above.

In the mounting table 24, one cavity 19 that communicates with aplurality of suction holes 2 is formed. The cavity 19 is formed in aportion other than the outer circumferential portion of the mountingtable 24.

The plurality of positioning pins 10 are provided, in a state ofprotruding upward, on the upper surface of the mounting table 24 on theouter circumferential side out from the cavity 19 (that is, thecircumference portion of the mounting table 24). Note that in FIG. 15,the positioning pins 10 are not illustrated.

The conductor 21 and the mounting table 24 are made of a conductivematerial such as oxygen-free copper, pure copper, iron-based metal, oraluminum. Further, the conductor 21 and the mounting table 24 may besubjected to a surface treatment such as gold plating.

The mounting table 24 and the vacuum tube 20 are formed integrally. Oneend portion of the vacuum tube 20 passes through the central portion ofa bottom surface of the mounting table 24 and is connected to the cavity19. Accordingly, one end portion of the vacuum tube 20 communicates withthe plurality of suction holes 2 through the cavity 19. Further, theother end portion of the vacuum tube 20 is connected to, for example, avacuum pump (not illustrated).

When air is sucked from the vacuum tube 20 connected to the centralportion of the bottom surface of the mounting table 24, the air suckedfrom the plurality of suction holes 2 flows toward the vacuum tube 20through the entire cavity 19. Consequently, the difference in suctionforce between the central portion and the outer circumference portion ofthe conductor 21 is reduced, so that the variation in suction forcewithin the plane of the semiconductor wafer 11 is reduced.

Further, the description of the semiconductor test method is omittedbecause of the same processes as those of Embodiment 2.

As described above, in Embodiment 6, the semiconductor test apparatusincludes the chuck top 9E on which the semiconductor wafer 11 ismounted, and the contact probes 15 that contact the measurement pointsof the semiconductor chips formed on the semiconductor wafer 11, thechuck top 9E includes the conductor 21 that contacts the lower surfaceof the semiconductor wafer 11, the mounting table 24 arranged below theconductor 21, and the vacuum tube 20 connected to the mounting table 24,the conductor 21 has the plurality of suction holes 2 formed therein, inthe mounting table 24, the cavity 19 that communicates with a pluralityof suction holes 2 is formed, and the vacuum tube 20 communicates withthe plurality of suction holes 2 through the cavity 19.

Therefore, the air sucked from the plurality of suction holes 2 flowstoward the vacuum tube 20 through the entire cavity 19, so that thevariation in the suction force within the plane of the semiconductorwafer 11 becomes small. As a result, a variation in the contactresistance between the semiconductor wafer 11 and the chuck top 9Ebecomes small; therefore, in the semiconductor test, the suppression oflowering in measurement accuracy due to a variation in the contactresistance between the semiconductor wafer 11 and the chuck top 9E isensured.

Embodiment 7

Next, a semiconductor test apparatus according to Embodiment 7 will bedescribed. FIG. 17 is a diagram of Embodiment 7, corresponding to FIG.16. In Embodiment 7, the same components as those described inEmbodiments 1 to 6 are designated by the same reference numerals, andthe description thereof is omitted.

As illustrated in FIG. 17, the chuck top 9F includes the conductor 21,the mounting table 24, and the vacuum tube 20. In Embodiment 7, theshape of the mounting table 24 is different from that in Embodiment 6.

The mounting table 24 is circular in top view and has a tapered shape inwhich the lower end portion is thinner than the upper end portion incross-sectional view. The mounting table 24 and the vacuum tube 20 areformed integrally, and the whole shape is formed into a funnel-likeshape.

One end portion of the vacuum tube 20 passes through the central portionof a bottom surface of the mounting table 24 and is connected to thecavity 19. Accordingly, one end portion of the vacuum tube 20communicates with the plurality of suction holes 2 through the cavity19. Further, the other end portion of the vacuum tube 20 is connectedto, for example, a vacuum pump (not illustrated).

Further, the description of the semiconductor test method is omittedbecause of the same processes as those of Embodiment 6.

As described above, in Embodiment 7, the mounting table 24 has a taperedshape in which the lower end portion is thinner than the upper endportion in cross-sectional view, so that the distance the sucked airflows from each suction hole 2 and reaches the vacuum tube 20 can bemade substantially the same. Consequently, the variation in the suctionforce in the plane of the semiconductor wafer 11 becomes smaller, andthe variation in the contact resistance between the semiconductor wafer11 and the chuck top 9 also becomes smaller than that in the case ofEmbodiment 6. As a result, in the semiconductor test, the suppression oflowering in measurement accuracy due to a variation in the contactresistance between the semiconductor wafer 11 and the chuck top 9 isfurther ensured than that in the case of Embodiment 6.

The Embodiments can be combined, appropriately modified or omitted.

While the invention has been illustrated and described in detail, theforegoing description is in all aspects illustrative and notrestrictive. It is therefore understood that numerous modifications andvariations can be devised without departing from the scope of theinvention.

What is claimed is:
 1. A semiconductor test apparatus comprising: achuck top on which a semiconductor wafer is mounted; and contact probesthat contact measurement points of semiconductor chips formed on thesemiconductor wafer, wherein the chuck top includes a conductor thatcontacts a lower surface of the semiconductor wafer, a mounting tablearranged below the conductor, and a first vacuum tube and a secondvacuum tube connected to the mounting table, the conductor has aplurality of suction holes arranged in a spiral form in top view, in themounting table, a flow pass communicating with the plurality of suctionholes and having a spiral form in top view is formed, the first vacuumtube is connected to an inner circumference portion of the flow pass,and the second vacuum tube is connected to an outer circumferenceportion of the flow pass.
 2. A semiconductor test apparatus comprising:a chuck top on which a semiconductor wafer is mounted; and contactprobes that contact measurement points of semiconductor chips formed onthe semiconductor wafer, wherein the chuck top includes a conductor thatcontacts a lower surface of the semiconductor wafer, a mounting tablearranged below the conductor, and a vacuum tube connected to themounting table, the conductor has a plurality of suction holes arrangedin a spiral form in top view, in the mounting table, a flow passcommunicating with the plurality of suction holes and having a spiralform in top view is formed, the vacuum tube is connected to an innercircumference portion of the flow pass, and cross-sectional shapes ofthe flow pass are larger on an outer circumferential side than on aninner circumferential side.
 3. The semiconductor test apparatusaccording to claim 1, wherein cross-sectional areas of the flow pass arelarger on an outer circumferential side than on an inner circumferentialside.
 4. The semiconductor test apparatus according to claim 1, whereinsizes of the plurality of suction holes are larger on an outercircumferential side than on an inner circumferential side.
 5. Thesemiconductor test apparatus according to claim 2, wherein sizes of theplurality of suction holes are larger on an outer circumferential sidethan on an inner circumferential side.
 6. A semiconductor test apparatuscomprising: a chuck top on which a semiconductor wafer is mounted; andcontact probes that contact measurement points of semiconductor chipsformed on the semiconductor wafer, wherein the chuck top includes aconductor that contacts a lower surface of the semiconductor wafer, amounting table arranged below the conductor, and a vacuum tube connectedto the mounting table, the conductor has a plurality of suction holes,in the mounting table, a cavity communicating with the plurality ofsuction holes is formed, and the vacuum tube communicates with theplurality of suction holes through the cavity.
 7. The semiconductor testapparatus according to claim 6, wherein the mounting table has a taperedshape in which a lower end portion is thinner than an upper end portionin cross-sectional view.
 8. A semiconductor test method using thesemiconductor test apparatus according to claim 1, comprising the stepsof: (a) mounting the semiconductor wafer on the chuck top; (b) suckingthe semiconductor wafer by the first vacuum tube, and sucking thesemiconductor wafer by the second vacuum tube, and (c) bringing thecontact probes into contact with the measurement portions of thesemiconductor chips to measure electrical characteristics of thesemiconductor chips.
 9. The semiconductor test method according to claim8, wherein the step (b) is a step of sucking the semiconductor wafer bythe first vacuum tube, and then sucking the semiconductor wafer by thesecond vacuum tube.
 10. A semiconductor test method using thesemiconductor test apparatus according to claim 2, comprising the stepsof: (d) mounting the semiconductor wafer on the chuck top; (e) suckingthe semiconductor wafer by the vacuum tube; and (f) bringing the contactprobes into contact with the measurement portions of the semiconductorchips to measure electrical characteristics of the semiconductor chips.11. A semiconductor test method using the semiconductor test apparatusaccording to claim 6, comprising the steps of: (d) mounting thesemiconductor wafer on the chuck top; (e) sucking the semiconductorwafer by the vacuum tube; and (f) bringing the contact probes intocontact with the measurement portions of the semiconductor chips tomeasure electrical characteristics of the semiconductor chips.